#nuclear spin

Physicists couple distant nuclear spins using a single electron

For the first time, researchers at the University of Basel in Switzerland have coupled the nuclear spins of distant atoms using just a single electron. Three research groups took part in this complex experiment, the results of which have now been published in the journal Nature Nanotechnology.

In most materials, the nuclear spins of neighboring atoms have only a very weak effect on one another, as the tiny nuclei are located deep within the atoms. This is not the case in metals, however, where some of the electrons are able to move freely. The electron spins are able to couple nuclear spins at relatively large distances from one another. Named after four physicists, this RKKY interaction was discovered in the 1950s.

Nuclear spins linked by an individual electron spin

Now, an experiment by researchers from the Department of Physics at the University of Basel has for the first time succeeded in demonstrating this mechanism with a single electron, describing it using quantum theory. The team led by Prof. Richard Warburton trapped a single electron inside a quantum dot. With use of a method developed in Basel to measure nuclear spin resonance, they showed that the electron coupled the spins of nuclei up to five nanometers apart -- a huge distance in the world of nuclear spins. The results are particularly relevant to the development of spin qubits: these seek to use electron spins to carry information, but the interaction with the nuclei limits the stability of the quantum information.